The fabrication of integrated circuits depends upon the construction of a desired pattern of electrically active impurities within a semiconductor body, and upon the formation of a corresponding interconnection pattern for their operating characteristics.
Fabrication of integrated circuits thus involves a great number of different processes well known in the art, examples being chemical vapor deposition of semiconductors and insulators, oxidation, solid state diffusion, ion implantation, vacuum deposition, various lithographic techniques and numerous types of etching techniques. A typical IC fabrication process utilizes a great number of cycles, each of which may utilize a specific sequence of one or more of the above referenced fabrication techniques.
As is well known in the art, films applied to the semiconductor may be used to selectively limit the effect of a certain process to a regionally specific area. When a film is used in this manner it is commonly referred to as being a mask. For example, in order to dope a regionally specific area on a semiconductor one may apply a film that is impermeable to the specific doping process to be utilized. After doping the desired region, the film may be removed.
It is necessary for the various films utilized in the IC fabrication process to be compatible with a large number of lithography, etching, doping and other IC fabrication techniques. However, the polyimides or spin-on glasses (SOG) commonly used as films today have a practical operating limit below 500.degree. C. This severely restricts the sequence of fabrication steps that can be employed in the presence of such films.
Therefore there exists a need for a film capable of application on semiconductor devices by methods known in the IC fabrication art that is capable of withstanding temperatures in excess of 500.degree. C. There further exists a need for such a film that is compatible with a wide range of IC fabrication processes such as various etching, doping, deposition and implantation techniques.